I'm getting at optimium trim 4200rpm but only 30mph. Engine is strong
with good
even compression.

Would going down in pitch (raising RPM) help any with top speed? We're not
skiers, we just want this for getting to the mainland from time to time.

Going UP in pitch can help your top end, but will also LOWER the RPMs
(higher gear on a car). Going DOWN in pitch will help your LOW end (hole
shot), and will RAISE ypur RPMs and possible over rev.

Something else is holding your speed down.

--Mike

"Josh Assing" wrote in message
...
Hi All.
We just added a power boat to our fleet (of otherwise sailboats)
1990 Four Winns Horizon 180
Cobra outdrive, 4.3L GM engine

The original owner has two zincs; but I can count 4 (it's in the water
right
now) -- QUestion: Does anyone know if there's a zinc behind the prop? Is
there
a place where I can just buy a "zinc kit" for the outdrive?

The "factory" prop is a 14.5 x 19 -- that's what's on there now; max RPM
is
supposed to be between 4200-4600 and running at 42-45mph

The factory prop is on there now -- it's an ugly thing with non-smooth
blades
(they appear welded to the hub) and nicks out of hte blade (ala running
thru mud
etc)

I'm getting at optimium trim 4200rpm but only 30mph. Engine is strong
with good
even compression.

Would going down in pitch (raising RPM) help any with top speed? We're
not
skiers, we just want this for getting to the mainland from time to time.

Oh -- and one thing that really bugs me -- the trim on these boats.... the
trim
guage always reads "UP" I suspect the sender is jammed/broken -- but --
should
it allow you to raise it to "trailer mode" while underway? This is the
1st boat
that's allowed me to do that.

Thanks for any advice
-josh


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